<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>propsData选项（option）</title> 
    </head>
    <body>
        <header></header>
        <script src = "https://unpkg.com/vue/dist/vue.min.js"></script>
        <script>
            var header_a = Vue.extend({//扩展
                template:`<p>{{ message }}</p>`,
                data:function(){
                    return {
                        message:'hello,I am header!'
                    }
                }
            });

            new header_a({propsData:{a:12}}).$mount('header');//挂载
        </script>
    </body>
</html>